When Human Eggs Become a Scrambled Mess
Up to a quarter of pregnancies are not carried to term; oftentimes an embryo is aborted by the body before a woman even knows she’s pregnant. The most common cause of miscarriage is egg aneuploidy—the oocyte contains too many or too few chromosomes. Aneuploidy is thus the leading genetic cause of infertility, and those embryos that are not miscarried can result in children with developmental disorders, such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Turner syndrome (monosomy X).